Exhaust antifreeze structure for pneumatically powered apparatus



May 1970 v A. J. GARTNER 3, 7

EXHAUST ANTIFREEZE STRUCTURE FOR PNEUMATICALLY POWERED APPARATUS Filed March 25, 1968 Albert J. Gartner,

to]: l by l Agejt United States Patent 3,509,917 EXHAUST ANTIFREEZE STRUCTURE FOR PNEUMATICALLY POWERED APPARATUS Albert J. Gartner, Westview, Texada Island, British Columbia, Canada, assignor to Kal-Pac Engineering Ltd., Kilkenny, North Vancouver, British Columbia, Canada, a corporation of Canada Filed Mar. 25, 1968, Ser. No. 715,772 Int. Cl. E03b 7 /12; F161 53/ US. Cl. 13832 17 Claims ABSTRACT OF THE DISCLOSURE For a pneumatic percussion drill, an exhaust antifreeze apparatus. An exhaust pipe in the exhaust port with a surrounding Water jacket. Water, flowing into the jacket preventing condensate freezing at the port and pipe, discharged through perforated outer end. Silencing by adding flexible exhaust extension.

FIELD OF THE INVENTION AND DESCRIPTION OF PRIOR ART The invention relates to a structure for inhibiting freezing of an exhaust pipe of a pneumatically powered apparatus, and more particularly inhibiting freezing of the exhaust of a pneumatic percussion drill.

It is well known in the mining industry that expansion at discharge from a pneumatically operated percussion drill results in freezing of condensate in an exhaust pipe secured to an exhaust port of the drill. Thus, the exhaust pipe can and does become fouled with ice so as to prevent proper operation of the drill necessitating shut downs.

In one device directed to reduce this difliculty, a flexible hose of a suitable plastic material is provided as a part of a exhaust system. Moisture condenses on the flexible hose and freezes, vibration and pulsation cause ice particles formed on the flexible pipe to break loose. Such devices are effective in many circumstances, but slush tends to form and can freeze thus necessitating a shut downalthough much less frequently than would be the casein a drill not so equipped.

United States Pat. 3,235,030 issued Feb. 15, 1966 to Lindberg in a Pneumatic Drill Muffler with Water Mingling Pipe. This patent teaches a muffler secured on the body of the drill over the exhaust port, with a central water pipe discharging a spray of water directly into the exhaust port of the drill so that this discharge is forced to travel outwards with the exhaust air to discharge through an exhaust hose. This ingenious structure will effect at least artial solution to the instant problem.

SUMMARY OF THE INVENTION The present invention provides exhaust anti-freeze structure including an exhaust pipe, an inner end of which is suitably secured in the exhaust port. An outer jacket surrounds the exhaust pipe, so that a water jacket is defined between the outer jacket and the exhaust pipe, and closure elements at inner and outer ends of the jacket. The inner closure is closely adjacent to and preferably contiguous to the exhaust port, and the outer closure is perforated. A water inlet pipe introduces water into the jacket, the intake pipe being inclined so as to direct entering water against the inner closure to circulate over and around it, thence to pass through the jacket to discharge through perforations of the outer closure.

Water, even cold water, obtained from a common mine supply is above freezing temperature, consequently the exhaust pipe, and particularly the inner closure against which the Water is directed upon entering, is maintained at a temperature which, in circumstances of ordinary use,

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is above freezing. Thus freezing-with consequent ice formation-is inhibited. The discharge from the perforations aforesaid is water, or ice particles and water, as a spray.

It is common knowledge that pneumatic drills are noisy and that the noise may reach a harmful level. In some mines, and in some countries, there are regulations requiring silencing devices. While it is well known to attach a flexible hose to the exhaust pipe of a pneumatic drill to lead the discharge away from the operator, and for other purposes, the present invention provides structure such, that with such a flexible hose fitted over the jacket to confine the exhaust, notwithstanding that the hose may be comparatively shortfour or five feet-a muflling effect results. Analysis of acoustic effects resulting in muflling or silencing is complex. Whatever the nature of the present mufliing action may be, the inventor has discovered that a comparatively short length of flexible tube secured 'over the jacket at its discharge end so to receive the discharge has material silencing effect. By material is meant, sufiicicnt to reduce noise to a level acceptable under present regulations.

A central concept of the invention is thus seen to be structure as above described to inhibit ice formation and freezing, an additional concept being that the addition of an exhaust hose a few feet long has material quieting effect when used in combination with the structure aforesaid.

DESCRIPTION OF THE DRAWINGS FIG. 1 shows a device according to the present invention attached to a pneumatic percussion drill.

FIG. 2 is a side elevation of the device, with parts broken away to show interior construction.

FIG. 3 is a section on 3-3 of FIG. 2.

FIG. 4 is a diagram to illustrate water flow, as seen from 44 in FIG. 2.

FIG. 5 shows an alternative exhaust pipe.

A detail description following is related to the drawings and shows, by way of example, preferred embodiment of the invention which, however, is capable of expression in strucctlure other than that particularly described and illustrate PREFERRED EMBODIMENT Description of FIG. 1

The exhaust antifreeze structure is indicated generally at 10, being shown secured to an exhaust port of a pneumatic percussion drill 11 operated by compressed air from the supply source, not shown, through an air line 12. Water supply from a source, not shown, passes to the device through a hose line 13.

Description of FIGS. 2 and 3 In FIG. 2, an exhaust pipe adapted to be secured in an exhaust port of the drill is designated 14, having an inner end threaded as seen at 15 to screw into the exhaust port. The exhaust pipe extends outwards from the inner end, suitably having an L-bend as seen at 16 and then extending to a straight outer part 17. The bend 16 is provided, as is common practice, as it is generally preferable to direct the exhaust downwards as seen in FIG. 1. The bend has no significance related to a central concept of the present invention but in one embodiment requires particular structure later described.

An outer jacket 18 is a pipe similarly shaped, an inner wall of the jacket defining with an outer Wall of the exhaust pipe a space annular in cross section, the space being designated 19 in FIG. 2. An inner annular closure 22 is provided closing an inner end of the jacket 18 and forming an inner end wall of the space 19. The threaded portion 15 of the exhaust pipe 14 extends to the inner closure as shown,-the position.

At an outer end of the exhaust pipe outer part 17 a perforated annular closure is provided defining an outer end wall of thes'pace 19. As bestseenin FIG. 3, the outer closure has a series of perforations spaced generally midway between inner and outer walls defining the closure, and spaced circumferentially as shown. In FIG. 3, one circular row of perforations is shown, an additional row or rows can be provided.

An exhaust hose 25 has an inside diameter such that the hose can be fitted tightly over the outer end of the outer jacket 1-8, and can be secured in the position by obvious clamp means, not shown. The outer walls of the jacket outer end can be provided with circular peripheral corrugations and, with an exhaust hose of suitable inside diameter, clamp securing means can be dispensed with. The exhaust hose itself is of suitable length as will later be explained.

Adjacent the inner closure 22, an outer wall of the jacket 18 has a water intake pipe 26 to which the water line 13 is obviously secured, the intake pipe being inclined to a longitudinal axis of the inner end of the exhaust pipe 14, so as to direct entering water against the inner closure 22. 7

It is seen that a water jacket is defined by an inner side wall of the jacket 18, an outer side wall of the exhaust pipe 14, the inner closure 22 and the outer perforated :losure 23 with water entering the intake pipe 26 and discharging through the perforations 24.

OPERATION Water passing through the Water line 13 as indicated by an arrow 31 FIGURE 2 passes through the intake 26 lowing as shown by arrows 32 and impinging against :he inner closure 22, then turning to flow outwards. as well the water circulates around and over the inner :losure 22 also flowing outwards as indicated by broken arrows 33. The water then passes through the water acket as indicated by arrows 33 and 34, to discharge :hrough the perforations 24 of the perforated closure 23 is indicated by arrows 35. The perforations act as nozales, consequently discharge throughthe perforations will be a series of jets forming, initially, an annular spray isually with ice.

Exhaust air from the exhaust port of the drill enters :he exhaust pipe as indicated by an arrow 41, flows hrough the exhaust pipe as indicated by an arrow 42 lischarging through the outer end of the exhaust pipe 18 indicated by an arrow 43. Ordinarily temperature of he water in the line 13 is well above freezing point, con- :equently with this water impinging against the inner :losure 22, temperature of the outer wall of the closure, )f the exhaust port itself, and the wall of the exhaust )ipe in this vicinity, will approach that of the water. Water supply might typically be 50, but operation is atisfactory with water at a much lower temperature.

The exhaust pipe preferably is of metal of high thernal conductivity, e.g. copper or brass, at least adjacent its breaded end, and the end closure 22 is also of metal of ligh thermal'conductivity. For optimum conduction the :losure 22 is contiguous to the exhaust port. Thermal :onductivity of the jacket 18 is generally unimportant- )llt where the drill is to be operated at low temperatures, agging can be provided so that heat flow is mainly to he end closure 22 and the exhaust pipe adjacent thereto, ather than outwards through walls of the jacket.

One purpose of the exhaust hose 25 is to lead the tater away from the drilling site to suitable drainage, ind the hose is as long as is required to effect this. Reduclon of noise working in confined underground condiions is of importance as has been pointed out. With the xhaust passing as indicated by the arrow 43, FIG. 2, utwards into the spray from the perforations 24, and Ilth both the spray and the exhaust mixing in the exclosure being obviously welded in 4 haust hose, material silencing efiect is observed even though the exhaust hose may be only four or 'five feet long.

ALTERNATIVE CONSTRUCTIONS It has been pointed out that water impinging on the end closure 22 will circulate around and over said closure. This is further illustrated diagrammatrically in FIG. 4 where impinging water flows, as shown by arrows 32.1 and 33.1, around the end closure. The water intake pipe 26 is inclined, as shown in FIG. 2, to cause water to impinge against the closure 22 and, as shown in FIG. 4, is radial of the annulus. That is, the pipe 26 is inclined to a longitudinal axis of the inner end of the exhaust pipe, and is disposed with its axis in a plane normal to and radial of the end closure-which disposition of the intake pipe 26 is hereinafter referred to as being disposed radiallyof the inner end closure.

The water intake pipe can be disposed inclined to the radial plane aforesaid as shown in broken outline at 26.1, that is the intake, while still inclined to the-longitudinal exhaust pipe axis, is also inclined to the said plane-Which disposition is hereinafter referred to as being disposed inclined to a radius of the end closure. In such case, flow would be clockwise (as viewed in FIG. 4) around the closure. An additional intake pipe as the pipe 26.1 can be provided as shown in broken outline at 26.2, for improved circulatory motion over the end closure-and an additional intake disposed as the intake 26 can also be provided, which latter alternative is not shown.

At least one intake pipe is thus provided inclined to direct water against the said closure circulating over and around it-the intake pipe being inclined to the exhaust pipe longitudinal axis, and disposed either radial of, or inclined to a radius of, the closure and preferably adjacent the inner end closure as shown.

In each alternative above, flow in the water jacket to and through the perforated outer closure is substantially as before .described with, however, helical flow taking place when an inlet pipe is inclined to a radius as aforesaid.

Where a pneumatic drill has been made for use with an antifreezing device according to the invention, the inner end closure 22 can be integral of the drill body. When the device is to be used with existing drills having more than one exhaust port, adaptation can be eifected by obvious attachment means other than the threading shown in FIG. 2.

While the inner closure 22 is to be as close to the drill exhaust port as is practical preferably in contact therewithand is integral in a drill made for use with the device-position of the outer closure 23 is relatively unimportant. Alternative to the position of FIG. 2 where this closure is at an outer end of the exhaust pipe, it can be disposed inwards as shown in broken outline at 23.1. In both cases above, the perforated end closure extends between an outer part of the exhaust pipe to the jacket and defines a perforated end wall of the water jacket space.

As pointed out in the description of FIG. 2 the exhaust pipe has a bend so that the exhaust can be directed downwards. It is common practice to provide for rotation so that the exhaust can be directed at will to either side. In FIG. 2 a thin locking nut is designated 44, the threaded inner end 15 can be screwed into the exhaust port with the nut against the inner closure 22. When the outer part 17 is disposed to direct the discharge as required, the locking nut is tightened so that the bent portion may be oriented in the desired direction, after which the lock nut is tightened to secure the pipe in that position. When the locking nut is secured in position the end closure is 1 spaced somewhat from the drill exhaust port tending to impair anti-icing at this point. I have however found that using material of high thermal conductivity as stated, and by providing a thin locking nut-say three or four sixteenths of an inch thick-satisfactory effect is still obtained.

FIG. alternative Alternatively the device can, as before implied, be straight, and a bend provided in the exhaust hose 25. In FIG. 5, which is at a small scale, structure generally as FIG. 2 but without the bend 16 is designated generally 10.1, an exhaust hose 25.1 having a bend 16.1 being shown in position. Thus, the hose may be rotated to dispose the bend as required. An obvious clamp, not shown, can be provided to secure the hose.

I claim:

1. Exhaust antifreeze structure for pneumatically powered apparatus, the structure including in combination:

(a) an exhaust pipe adapted to be secured at an inner end thereof to an exhaust port of the pneumatically powered apparatus,

(b) an outer jacket having a wall, a water jacket being defined by the jacket Wall, an outer wall of the exhaust pipe, an inner closure, and a perforated outer closure,

(0) at least one intake pipe for introducing water into the jacket, the intake pipe being inclined to direct the water against the inner closure circulating over and around it and passing to discharge through the perforated outer closure.

2. Structure as defined in claim 1, the inclined intake pipe being disposed radially of the inner end closure and inclined to a longitudinal axis of the exhaust pipe.

3. Structure as defined in claim 1, the inclined intake pipe being disposed inclined to a radius of the end closure, and inclined to a longitudinal axis of the exhaust pipe.

4. Structure as defined in claim 2 and an exhaust hose fitted over an outer end of the outer jacket.

5. Structure as defined in claim 3, and an exhaust hose fitted over an outer end of the outer jacket.

6. Structure as defined in claim 1, the inner end closure being contiguous to the exhaust port.

7. Structure as defined in claim 6, the exhaust port and at least a part of the exhaust pipe adjacent the inner closure being of metal of high thermal conductivity.

8. Structure as defined in claim 2, the exhaust port and at least a part of the exhaust pipe adjacent the inner closure being of metal of high thermal conductivity.

9. Structure as defined in claim 3, the exhaust port and at least a part of the exhaust pipe adjacent the inner closure being of metal of high thermal conductivity.

10. Structure as defined in claim 2 and an exhaust hose fitted over an outer end of the outer jacket, the inner end closure being contiguous to the exhaust port, the exhaust port and at least a part of the exhaust pipe adjacent the inner closure being of metal of high thermal conductivity.

11. Structure as defined in claim 3 and an exhaust hose fitted over an outer end of the outer jacket, the inner end closure being contiguous to the exhaust port, the exhaust port and at least a part of the exhaust pipe adjacent the inner closure being of metal of high thermal conductivity.

12. Structure as defined in claim 10, the exhaust pipe having an L-bend.

13. Structure as defined in claim 11, the exhaust pipe having an L-bend.

14. Structure as defined in claim 10, the exhaust pipe being straight and the exhaust hose having an L-bend adjacent the outer end of the outer jacket.

15. Structure as defined in claim 11, the exhaust pipe being straight and the exhaust hose having an L-bend adjacent the outer end of the outer jacket.

16. Structure as defined in claim 2, the exhaust pipe having an L-bend, the inner end of the exhaust pipe being threaded for securing as aforesaid to the exhaust port, and a thin locknut disposed between the exhaust port and the inner closure adapted so that the L-bend can be oriented in a desired direction and secured by the locknut.

17. Structure as defined in claim 3, the exhaust pipe having an L-bend, the inner end of the exhaust pipe being threaded for securing as aforesaid to the exhaust port, and a thin locknut disposed between the exhaust port and the inner closure adapted so that the L-bend can be oriented in a desired direction and secured by the locknut.

References Cited UNITED STATES PATENTS 2,958,183 11/1960 Singleman 138111 X 3,208,539 9/1965 Henderson 138-414- HOUSTON S. BELL, JR., Primary Examiner US. Cl. X.R. 138-114 

